Reticle constructions, and methods for photo-processing photo-imageable material

ABSTRACT

The invention includes methods for photo-processing photo-imageable material. Locations of the photo-imageable material where flare hot spots are expected to occur are ascertained. A substantially uniform dose of light intensity is provided to at least the majority of the photo-imageable material other than the hot spot locations, and is not provided to the hot spot locations. The provision of the substantially uniform dose of light intensity can occur during formation of a primary pattern in the photo-imageable material with a reticle, utilizing the same reticle as that used for making the primary pattern; or can occur at a separate processing stage than that utilized for forming the primary pattern and with a separate reticle from that utilized to form the primary pattern. The invention also includes reticle constructions which can be utilized for photo-processing of photo-imageable material.

TECHNICAL FIELD

The invention pertains to reticle constructions, and to methods forphoto-processing photo-imageable material.

BACKGROUND OF THE INVENTION

Photolithography is commonly used during formation of integratedcircuits on semiconductor wafers. More specifically, a form of radiantenergy is passed through a radiation-patterning tool and onto aradiation-sensitive material associated with a semiconductor wafer. Theradiant energy can be referred to as actinic energy, and will typicallybe light in the ultraviolet (UV) range or visible range. Theradiation-sensitive material is a photo-imageable material, such as, forexample, photoresist.

The radiation-patterning tool can be referred to as a photomask or areticle. The term “photomask” traditionally is understood to refer tomasks which define a pattern for an entirety of a wafer, and the term“reticle” is traditionally understood to refer to a patterning toolwhich defines a pattern for only a portion of a wafer. However, theterms “photomask” (or more generally “mask”) and “reticle” arefrequently used interchangeably in modern parlance, so that either termcan refer to a radiation-patterning tool that encompasses either aportion or an entirety of a wafer. For purposes of interpreting thisdisclosure and the claims that follow, the terms “reticle” and“photomask” are utilized with their traditional meanings.

Advances in semiconductor integrated circuit performance have typicallybeen accompanied by a simultaneous decrease in integrated circuit devicedimensions and a decrease in the dimensions of conductor elements whichconnect those integrated circuit devices. The demand for ever smallerintegrated circuit devices brings with it demands for ever-decreasingdimensions of structural elements, and ever-increasing requirements forprecision and accuracy in radiation patterning. Accordingly, it isdesired to develop improved tools and processes for radiationpatterning.

SUMMARY OF THE INVENTION

In one aspect, the invention encompasses a method of photo-processingphoto-imageable material. A semiconductor substrate is provided, withthe substrate having a photo-imageable material thereover. Locations ofthe photo-imageable material where flare hot spots are expected to occurare determined. Such locations are defined as hot spot locations, andthe remainder of the photo-imageable material is defined as a non-flarelocation. A substantially uniform dose of light intensity is provided toat least the majority of the non-flare location and not to the hot spotlocations. The light can comprise any suitable wavelength ofelectromagnetic radiation, but typically will be in the UV or visiblerange.

In one aspect, the invention includes a method of forming a pattern oflight intensity across an expanse of photo-imageable material. A reticleis provided which is configured to generate a primary pattern ofdifferent intensities from light passing therethrough. The reticle isstepped to different locations over the photo-imageable material, andlight is provided to the reticle at the different locations to form aseries of primary patterns across the photo-imageable material. Thelight also forms flare regions of light intensity in locations of thephoto-imageable material during the formation of the primary patterns.The locations of the flare regions in the photo-imageable material aredefined as flare locations, and the remainder of the photo-imageablematerial is defined as a non-flare location. The flare locations haveareas of maximum flare intensity. A substantially uniform dose of lightintensity is provided to at least the majority of the non-flare locationand not to the areas of maximum flare intensity of the flare locations.

In one aspect, the invention includes a method of utilizing a reticle topattern an expanse of photo-imageable material. A reticle is provided.The reticle is configured to be stepped across the expanse ofphoto-imageable material to provide a series of repeating patterns oflight intensity onto the photo-imageable material. The reticle isdivided into a main-field region and a compensating region. Themain-field region is configured to generate a primary pattern ofdifferent intensities from light passing therethrough, and has a firsttotal area. The compensating region has a second total area which is atleast about 25% of the first total area. The compensating region isconfigured to provide a substantially uniform intensity across theentirety of the second total area from the light passing therethrough.Light is passed through the reticle and then onto the photo-imageablematerial. The light passing through the main-field region forms theprimary pattern on the photo-imageable material. The light passingthrough the main-field region also forms one or more flare regions onthe photo-imageable material outside of the primary pattern. The lightpassing through the compensating region forms the substantially uniformintensity across the segment of the photo-imageable material extendingsubstantially entirely from the primary pattern to at least one of theflare regions. The substantially uniform intensity is substantiallyequal to an intensity of at least one of the flare regions.

In one aspect, the invention includes a reticle configured to be steppedacross an expanse of photo-imageable material to provide a series ofrepeating light-intensity patterns onto the photo-imageable material.The reticle includes a reticle substrate. A main-field region of thesubstrate is configured to generate a primary pattern of differentintensities from light passing therethrough. The main-field regiongenerates flare proximate the primary pattern when generating theprimary pattern. The main-field region has a first total area. Thereticle also includes a compensating region of the substrate proximatethe main-field region. The compensating region has a second total areawhich is at least about 25% of the first total area. The compensatingregion is configured to generate substantially uniform intensity acrossthe entirety of the second total area from light passing therethrough.The substantially uniform intensity is about the same as an intensity ofthe flare generated from the main-field region of the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below withreference to the following accompanying drawings.

FIG. 1 is a diagrammatic top view of a fragment of a reticle.

FIG. 2 is a diagrammatic, cross-sectional view of a fragment of areticle and a fragment of a semiconductor substrate shown at aprocessing stage in which the reticle is utilized to pattern lightdirected toward the semiconductor substrate.

FIG. 3 is a diagrammatic top view of a semiconductor substrateillustrating a region exposed during photo-processing.

FIG. 4 is a graphical view of radiation intensity across the FIG. 3exposed region. The graph of FIG. 4 is along the line 4-4 of FIG. 3.

FIG. 5 is a diagrammatic view of a fragment of a photo-imageablematerial illustrating an exemplary pattern of intensity that can beformed during photo-processing as a reticle is stepped across thephoto-imageable material.

FIG. 6 is a graphical view of radiation intensity across the FIG. 5exposed region. The graph of FIG. 6 is along the line 6-6 of FIG. 5.

FIG. 7 is a diagrammatic, cross-sectional view of an exemplary reticleof the present invention and a semiconductor substrate shown at aprocessing stage in which light patterned with the reticle is directedtoward the semiconductor substrate.

FIG. 8 is a graphical representation of radiation intensity that can beobtained with the FIG. 7 reticle, with the FIG. 8 graph corresponding toa processing stage comparable to that described with the FIG. 6 graph.

FIG. 9 is a diagrammatic, top view of a fragment of a reticleillustrating an exemplary relationship of a compensating region to aprimary region in accordance with one aspect of the present invention.

FIG. 10 is a diagrammatic, cross-sectional view of an embodiment of areticle which can be utilized for photo-processing in accordance withexemplary aspects of the present invention.

FIG. 11 is a diagrammatic top view of a reticle fragment illustrating anexemplary pattern that can be utilized in a compensating region inaccordance with one aspect of the present invention.

FIG. 12 is a diagrammatic top view of a reticle fragment illustrating anexemplary pattern that can be utilized in a compensating region inaccordance with another aspect of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This disclosure of the invention is submitted in furtherance of theconstitutional purposes of the U.S. Patent Laws “to promote the progressof science and useful arts” (Article 1, Section 8).

One aspect of the present invention is a recognition that flare regionsformed during photolithographic processing can problematically interferewith formation of desired patterns in photo-imageable material. Afurther aspect of the invention includes strategies for addressingproblems created by flare regions, and includes reticle substratessuitable for utilization in such strategies.

In some aspects, the invention includes recognition that the aerialimage intensity of patterned radiation at any image point across aradiation-imageable material is the sum of a constant part and amodulating part. The modulating part carries the image information andthe constant part provides the exposure power. It is desired for the sumto be uniform over an entire image to provide critical dimension (CD)control over the entire exposure area. Localized flare increases theconstant part locally and makes the exposure non-uniform over the imagearea. This degrades the CD uniformity and the process control, therebylimiting yield. In exemplary aspects, this problem is addressed byimproving the uniformity of the constant part and thereby the uniformityof the printed features.

Problems caused by flare regions are discussed with reference to FIGS.1-6, and strategies which can be utilized for addressing such problemsare discussed with reference to FIGS. 7-12.

An exemplary reticle construction 10 is illustrated in FIG. 1. Thereticle construction includes a so-called main-field region 12, and aperipheral region 14 surrounding the main-field region. A dashed-line 15is provided to diagrammatically illustrate a boundary between theperipheral region 14 and the main-field region 12.

The main-field region is configured to pattern actinic energy (in otherwords, light) passing therethrough. The patterned light can then beimpacted on a photo-imageable material and utilized to form a desiredpattern within the photo-imageable material. Photo-imageable material iscommonly photoresist, which can be either a positive resist or anegative resist. The patterned photo-imageable material can subsequentlybe utilized as a mask over a semiconductor substrate during fabricationof devices associated with the semiconductor substrate.

The region 14 provides a handle for manipulating construction 10 duringthe fabrication of main-field region 12, as well as during theutilization of main-field region 12 in a photolithographic process.

Referring next to FIG. 2, such illustrates a diagrammatic,cross-sectional view of the exemplary reticle construction 10 during aphotolithographic process. The reticle construction comprises themain-field region 12 and peripheral region 14 discussed previously, withthe main-field region being shown in more detail in FIG. 2 than in FIG.1.

Reticle construction 10 is shown comprising a base 16, a first layer 18directly against the base, and a second layer 20 directly against thefirst layer. The base 16 can be a relatively transparent material, suchas, for example, quartz; the first layer 18 can be a material ofintermediate transparency, such as, for example, molybdenum silicide;and the second layer 20 can be a relatively opaque material, such as,for example, a material comprising, consisting essentially of, orconsisting of chromium.

The terms “relatively transparent” and “relatively opaque” are utilizedto indicate that the materials 16 and 20 are transparent and opaque,respectively, relative to one another. Material 16 will typically besubstantially entirely transparent, and accordingly will typically havea transmittance of about 100%. Material 20 will typically besubstantially entirely opaque, and accordingly will typically have atransmittance of about 0%. Material 18 will have a transparencyintermediate the transparency of base 16 and layer 20, and can have atransmittance of, for example, about 6%.

In particular aspects, the base 16 can be considered to have a baseamount of transmission, the first layer 18 can be considered to have afirst amount of transmission, and the second layer 20 can be consideredto have second amount of transmission; with the base amount oftransmission being greater than the first amount of transmission whichis in turn greater than the second amount of transmission.

In the shown orientation, base 16 is over layer 18, which in turn isover layer 20. It is to be understood, however, that the reticleconstruction 10 can also be described in an inverse orientation relativeto that shown, in which layer 18 is over base 16 and layer 20 is overlayer 18.

The main-field region 12 is shown having a plurality of patternedfeatures 22, 24, 26 and 28 provided therein, and having a series of gaps21, 23, 25, 27 and 29 between the features. Some of the features containthe relatively opaque material 20 (features 24 and 26) while others onlycontain the intermediate transparency material 18 (features 22 and 28).Features 24 and 26 will substantially block light, while the features 22and 28 will reduce an intensity of the light passing therethroughwithout entirely blocking the light. Features 22 and 28 can be used forchanging more than just an intensity of the light. For example, features22 and 28 can be used to impose a phase-shift on the light.

Exemplary light (i.e., actinic energy) 30 is shown directed towardreticle 10 from above the reticle, and is shown passing through themain-field of the reticle. The light is patterned by the main-field ofthe reticle. Specifically, the light passing from the main-field of thereticle has a primary pattern of intensity imposed by the reticle.

A semiconductor construction 40 is shown beneath the reticle toillustrate utilization of the patterned light formed with the reticle.The construction 40 comprises a substrate 42 having a photo-imageablematerial 44 thereover.

Substrate 42 can comprise a monocrystalline silicon wafer at aprocessing stage of integrated circuit fabrication, and accordinglyhaving various materials associated therewith. To aid in interpretationof the claims that follow, the terms “semiconductive substrate” and“semiconductor substrate” are defined to mean any constructioncomprising semiconductive material, including, but not limited to, bulksemiconductive materials such as a semiconductive wafer (either alone orin assemblies comprising other materials thereon), and semiconductivematerial layers (either alone or in assemblies comprising othermaterials). The term “substrate” refers to any supporting structure,including, but not limited to, the semiconductive substrates describedabove.

Photo-imageable material 44 can comprise, consist essentially of, orconsist of photoresist.

Light patterned by the main-field 12 of the reticle forms a primaryradiation intensity (i.e., light intensity) pattern 46 withinphoto-imageable material 44. The general location of the primary patternis bounded by dashed-lines 47, and features of the primary pattern areillustrated by dashed-lines 49, 50 and 51.

The intensity of radiation within primary pattern 46 is diagrammaticallyillustrated by the depth of the radiation within material 44, withdeeper regions indicating higher intensity and less deep regionsindicating less intensity. The primary pattern has high-intensityregions 60, 62, 64, 66 and 68 corresponding to areas where radiation haspassed through gaps 21, 23, 25, 27 and 29, respectively, of themain-field region 12 of the reticle. The primary pattern also haszero-intensity regions 70 and 72 where the radiation has been blocked byfeatures 24 and 26, respectively, of the main-field region.Additionally, the primary pattern has intermediate intensity regions 74and 76 where the radiation has been partially-blocked by features 22 and28, respectively, of the main-field region.

Although most of the radiation (in other words, light) passing throughthe reticle is scattered along the way to the substrate with relativelysmall-angle so that the radiation remains directed primarily along theoriginal path that the radiation had in entering the reticle, some ofthe radiation can be scattered at a higher angle. Radiation scattered ata relatively high angle is represented by the arrows 80 and 82 in FIG.2. The high-angle scattered radiation can form so-called flare regions90 outside of the primary pattern 46.

The flare regions can interfere with subsequent processing ofphoto-imageable material 44. It is common for the flare regions tocomprise about the same intensity as one another, as shown. Theintensity within each flare region can be uniform, or can vary. Forinstance, at least some of the flare regions can comprise a central hotspot and intensity gradients around the hot spot. Alternatively, each ofthe flare regions can comprise about a uniform intensity across itsentirety. The illustrated flare regions have central hot spots andintensity gradients around the hot spots.

After the intensity pattern is formed within the photo-imageablematerial 44, the material 44 can be subjected to development with anappropriate solvent to selectively remove either exposed or non-exposedregions of the material. The development will thus transfer a patterninto the material corresponding to either the shown pattern of intensityor an inverse of the shown pattern of intensity. Prior to thedevelopment of the pattern within material 44, however, the reticle willbe stepped multiple times across the semiconductor substrate.

FIG. 3 shows a top view of semiconductor construction 40 at a processingstage in which the reticle has formed a single step over thesemiconductor substrate. FIG. 3 diagrammatically illustrates the primarypattern 46 flanked by flare regions 90. In the shown construction, theflare regions are on opposing lateral sides of the primary pattern. Itis to be understood, however, that the flare regions can occur on morethan two opposing sides of the primary pattern, on only one side of theprimary pattern, or in numerous other configurations depending on, amongother things, the configuration of the reticle utilized to form theprimary pattern, the wavelength of light passing through the reticle,and the distance between the reticle and the underlying semiconductorsubstrate during photolithographic processing with the reticle. In anyevent, the locations of the flare regions can be predicted for a givensemiconductor process. The predictions can be based on, for example, oneor both of calculations based on the various parameters that would beutilized during photo-imaging, and actual experiments utilizing areticle in a processing apparatus with a semiconductor substrate.

A line 4-4 is shown passing through primary pattern 46 and flarelocations 90. FIG. 4 diagrammatically illustrates a graph of intensityversus distance in the X direction along such line. The graph showssmall intensity peaks corresponding to flare locations 90, and shows alarge intensity peak corresponding to the location of primary pattern46. It is noted that, as discussed above with reference to FIG. 2, theprimary pattern would actually have a series of high intensity regionsand low intensity regions formed therein. The primary pattern is,however, shown having a single uniform high intensity in thediagrammatic representations of FIGS. 3 and 4 to simplify the discussionthat follows.

FIG. 5 shows a pattern that results as the reticle is stepped acrosssubstrate 40 to form a series of primary patterns. The series includesprimary patterns 100 and 102 in addition to the pattern 46. The primarypattern 46 has the flare regions 90 associated therewith, the primaryregion 100 similarly has flare regions 101 associated therewith, andprimary region 102 has flare regions 103 associated therewith. Thediagram of FIG. 5 shows a construction in which the reticle has beenstepped over three separate locations of a semiconductor substrate toform three repeats of the primary pattern. It is to be understood thatthe reticle would typically be stepped more than three times tosubstantially entirely cover the wafer with the repeating primarypattern.

A line 6-6 is shown extending across the patterned intensity regions ofFIG. 5. FIG. 6 shows the variation of intensity along line 6-6, andshows flare regions 90, 101 and 103 creating variations on the primarypatterns 46, 100 and 102. An interface between primary pattern 46 andprimary pattern 90 is diagrammatically illustrated with dashed-line 43,and an interface between primary pattern 90 and primary pattern 102 isdiagrammatically illustrated with a dashed-line 45.

The graph of FIG. 6 shows that flare regions can impose undulations ofintensity on the intensities of the primary patterns. Such candetrimentally cause a pattern ultimately developed in a photo-imageablematerial to be different than that which would be developed if the flareregion undulations had not been present. It is therefore desired toremove the flare region undulations. One strategy for removing the flareregion undulations would be to eliminate flare, but such is typicallynot practical. Another strategy is to provide additive radiation toregions between the flare regions so that the flare region undulationsare no longer discernible, or at least no longer problematic.

FIGS. 7 and 8 illustrate an exemplary process by which additiveradiation can be provided to regions between flare regions. In referringto FIGS. 7 and 8, similar numbering will be used as was utilized abovein describing FIGS. 1-6, where appropriate. FIG. 7 illustrates apreliminary stage in a photolithographic process in which light 30 ispassed through a reticle 200 to pattern the light, and in which thepatterned light is impacted on a photo-imageable material 44. Thephoto-imageable material is supported by a semiconductor substrate 42,and is part of a semiconductor construction 40.

Reticle 200 comprises the base 16, first layer 18, and second layer 20discussed above with reference to reticle 10 of FIG. 2. Reticle 200 alsocomprises the main-field 12 and peripheral region 14 discussed above.The reticle 200 differs from the reticle 10 of FIG. 2 in that reticle200 comprises segments 202 of the peripheral region from which opaquematerial 20 has been removed. Light can pass through segments 202 of theperipheral region 14, and the segments are configured to be inappropriate locations such that light passing therethrough will extendbetween the flare locations and the primary pattern 46 formed in thephoto-imageable material 44.

In some aspects of the invention, all portions of photo-imageablematerial 44 that are not within flare regions can be referred to asnon-flare locations, and the locations of the flare regions can bereferred to as flare locations. As discussed above, the flares can haveindividual hot spots associated therewith so that the intensity of theflares varies within the individual flare regions, or can have arelatively constant intensity throughout such that the entire flareregion can be considered a uniform hot spot. The locations of flare hotspots can be considered hot spot locations. If a flare has a peakintensity at the center, the flare can be considered to have a hot spotlocation centrally located within a flare location. For instance, theflare locations 90 of FIG. 7 are shown having peak intensity in thecenter and less intensity at the edges. Accordingly, the central regionsof the flare locations can be considered to be hot spot locationscentrally located within the flare locations.

Light passing through segment 202 forms segments 210 and 212 ofradiation intensity within photo-imageable material 44. Such segments ofintensity extend from flare locations 90 to primary patterned region 46.The segment 210 is shown extending only to an edge of the flare location90 at the left-most side of the FIG. 7 cross-section of construction 40,whereas the segment 212 is shown extending across some of the right-mostflare location 90 and extending to about a hot spot of the flarelocation 90. Segments 210 and 212 thus illustrate two slightly differentapproaches for providing radiation intensity within a photo-imageablematerial. Either or both of the approaches can be utilized in exemplaryapplications.

The intensity of segments 210 and 212 is substantially uniform, andaccordingly corresponds to a substantially uniform dose of lightintensity provided to non-flare locations of photo-imageable material44. It can be preferred that such dose of light intensity be about thesame as the intensity of the majority of the flare locations, or atleast about the same as the intensity of the hot spots of the flarelocations. In some aspects, the substantially uniform dose of lightintensity can be about the same as an expected maximum intensity of theflare regions, or about the same as an expected average intensity of theflare regions.

The intensity of segments 210 and 212 can be considered to be about thesame as the intensity of the flare regions if the intensity of thesegments effectively cancels the undulations in intensity that wouldotherwise be caused by the flare regions. In other words, if theproblems discussed above with reference to FIG. 6 are avoided. Inparticular aspects, the segments 210 and 212 can have an intensity thatis within about 5% of the maximum intensity of the hot spots of theflare regions 90.

The portions 202 of the reticle peripheral region 14 can be consideredto compensate for problems induced by the flare regions, and accordinglycan be referred to as segments of a compensating region in some aspectsof the invention. Preferably the compensating region will be utilized toprovide a substantially uniform dose of radiation to at least themajority of the non-flare location of a photo-imageable material, and insome aspects the compensating region will be utilized to provide asubstantially uniform dose of radiation to the entirety of the non-flarelocation of a photo-imageable material.

FIG. 8 shows a graph of intensity similar to the graph of FIG. 6, butthe graph if FIG. 8 shows utilization of the reticle of FIG. 7 insteadof the reticle of FIG. 2. Specifically, the compensating region 202 hascancelled most of the undulations previously caused by the flareregions. FIG. 8 is illustrated with the same numbering as that utilizedin FIG. 6, and accordingly shows regions 46, 100 and 102 correspondingto three steps of the reticle. However, in the aspect of FIG. 8 suchthree steps would be conducted with the reticle 200, whereas in theaspect of FIG. 6 such three steps were conducted with the reticle 10 ofFIG. 2.

It is noted that FIG. 8 shows that the reticle can treat all non-flareregions of an image pattern, but that the edges of the pattern will notbe overlapped by a main-field. Accordingly, low-intensity corners 220are illustrated occurring at peripheral edges of segments 46 and 102.

FIGS. 7 and 8 show an aspect in which a compensating region of a reticleextends over flare regions generated by the reticle. In some aspects,the compensating region of the reticle may not reach to the flareregions generated by the main-field of the reticle. In such aspects, thereticle can be configured so that the main-field creates an image for aparticular step of the reticle simultaneously with the compensatingregion providing a uniform dose of intensity around flare regions formedduring a neighboring step of the reticle. Thus, adjacent steps of thereticle can form partially overlapping patterns in a photo-imageablematerial, with the overlap being utilized to provide additive intensityto compensate for flares.

The reticle 200 of FIG. 7 can have a general shape similar to that ofthe FIG. 1 reticle. FIG. 9 shows top view of the reticle 200, and showsthat the reticle comprises the main-field 12 and peripheral region 14described previously, with the boundary 15 being provided to illustratean interface between the main-field and peripheral regions. FIG. 9 alsoshows a compensating region 262 within a portion of the peripheralregion, and extending entirely around the main-field region. Althoughthe shown compensating region is within only a portion of the peripheralregion, the invention also includes aspects in which the entirety of theperipheral region is a compensating region. Also, although the showncompensating region extends entirely around the main-field region, theinvention also includes aspects in which the compensating region isalong only a portion of the periphery of the main-field region.

In particular applications of the present invention, the main-fieldregion can be considered to have first total area, which is the overallarea of the main-field region. The compensating region can be eithersome or all of the peripheral region 14, and can have a total area whichis at least 25% of the first total area of the main-field region, atleast 50% of the first total area, or even at least 75% of the firsttotal area. The reticle of FIG. 9 has a main-field bounded by asubstantially rectangular periphery, and accordingly the main-field hasfour primary sides. The rectangular periphery can be considered tocomprise a total distance, and the compensating region can extend alongat least 25% of such distance, along at least 50% of such distance, oreven along at least 100% of such distance. Accordingly, the compensatingregion can extend along at least half of the primary sides of themain-field region, or in some aspects along all of the primary sides ofthe main-field region.

The amount of compensating region can vary depending upon the locationof the flares. For instance, if the flares only occur on opposinglateral sides of the primary pattern formed with the reticle, then thecompensating region can be formed only on the opposing sides of themain-field of the reticle. On the other hand, if the flares occur aroundall of the sides of a primary pattern formed with the reticle, then itcan be desired to form the compensating region to be around all of theprimary sides of the main-field of the reticle.

The application of FIG. 7 incorporates the compensating region into thesame reticle as the main-field region. Accordingly, the substantiallyuniform dose of light intensity is formed with the compensating regionat the same time that the primary pattern is formed with the main-fieldregion. It is to be understood, however, that at least some of theadditional dose of radiation provided to non-flare locations can beprovided with a second reticle or photomask that does not contain amain-field region. FIG. 10 illustrates a fragment of aradiation-patterning tool 250 (such tool can be either a reticle orphotomask) configured solely to provide compensating regions tonon-flare locations of a photo-imageable material.

The construction 250 comprises the base 16, first layer 18, and secondlayer 20 described previously. The first layer 20 (i.e., the relativelyopaque material) is patterned solely to overlap flare locations of aphoto-imageable material, and the remainder of the construction 250 isformed to provide a substantially uniform dose of light intensity to thenon-flare locations of the photo-imageable material.

The tool 250 can be utilized in combination with a tool of the typedescribed in FIG. 7. Accordingly, one of the tools will have both amain-field region and a compensating region, and the other tool willhave only the compensating region. Alternatively, the reticle having thecompensating region without a main-field region can be utilized incombination with a reticle which has only a main-field region (i.e., atool without any compensating region).

In two-reticle processes in which one of the reticles has a main-fieldregion and the other has only a compensating region, the reticles can beutilized in any order relative to one another. Accordingly, thesubstantially uniform dose provided to compensate for flare hot spotscan be provided before or after the occurrence of the flare hot spots.If the tool of FIG. 10 is a reticle, such reticle can be stepped in asimilar pattern as the reticle having the main-field region, or can bestepped in a different pattern. If the tool of FIG. 10 is a photomask,then the tool will cover an entire expanse of a photo-imageable materialat once, and will not be stepped.

In some aspects, a tool with only the compensating region can beutilized to fix a periphery around a patterned portion of aphoto-imageable material. For instance, as discussed above, a reticlecan be configured so that adjacent steps of the reticle form partiallyoverlapping patterns in a photo-imageable material, with the overlapbeing utilized to provide additive intensity to compensate for flares.The images formed in the photo-imageable material from peripheral stepsof such reticle may not be treated to the same extent as the imagesformed from non-peripheral steps. In such instances, a tool with onlythe compensating region can be utilized to fix the periphery around apatterned portion of the photo-imageable material.

The configuration of the compensating region shown and discussed withreference to FIGS. 7-10 is but one exemplary configuration of acompensating region. It is to be understood that compensating regionscan be formed with any configuration that directs a substantiallyuniform dose of radiation toward a substrate, preferably withoutinducing problematic flare locations.

FIGS. 11 and 12 illustrate a couple of additional configurations (270and 280, respectively) that can be incorporated into compensatingregions. Each of the constructions is shown to comprise a main-fieldregion 12, a peripheral region 14 around the main-field region, and acompensating region within the peripheral region. The construction ofFIG. 11 has a compensating region comprising a grating 272 formed toextend through one or more relatively opaque materials of the reticle.Radiation (i.e., light) can pass through the grating to provide asubstantially uniform dose of radiation intensity to a photo-imageablematerial during photo-processing. The construction of FIG. 12 has acompensating region 282 comprising a plurality of small orifices orholes extending through one or more relatively opaque materials of thereticle. The orifices allow some radiation to pass therethrough and forma substantially uniform dose of radiation intensity that can be appliedto non-flare regions of a photo-imageable material.

The grating 272 of FIG. 11 and the plurality of holes 282 of FIG. 12 caneach be considered to be exemplary of a compensating region comprising aplurality of closely-spaced features formed within a substantiallyopaque material. The substantially opaque material can be, for example,the material 20 and/or material 18 of the exemplary reticles 10 and 200of FIG. 2 and FIG. 7.

Flare can result from numerous causes, including, for example, defectsin a lens, lens coating, lens design or lens housing. The flare cancause over-exposure in unintended locations of a photo-imageablematerial. The methodology of the present invention provides additionalexposure to regions outside of hot spots, which can cause a more uniformbackground dose across an entire patterned field of a photo-imageablematerial than would result without such treatment.

In compliance with the statute, the invention has been described inlanguage more or less specific as to structural and methodical features.It is to be understood, however, that the invention is not limited tothe specific features shown and described, since the means hereindisclosed comprise preferred forms of putting the invention into effect.The invention is, therefore, claimed in any of its forms ormodifications within the proper scope of the appended claimsappropriately interpreted in accordance with the doctrine ofequivalents.

1. A method for photo-processing photo-imageable material, comprising:providing a semiconductor substrate having a photo-imageable materialthereover; determining locations of the photo-imageable material whereflare hot spots are expected to occur, such locations being defined ashot spot locations and the remainder of the photo-imageable materialbeing defined as a non-flare location; and providing a substantiallyuniform dose of light intensity to at least the majority of thenon-flare location and not to the hot spot locations.
 2. The method ofclaim 1 wherein at least some of the substantially uniform dose isprovided prior to occurrence of the flare hot spots.
 3. The method ofclaim 1 wherein at least some of the substantially uniform dose isprovided after occurrence of the flare hot spots.
 4. The method of claim1 wherein the substantially uniform dose is provided by light passingthrough a reticle.
 5. The method of claim 1 wherein the substantiallyuniform dose is provided by light passing through a photomask.
 6. Themethod of claim 1 wherein the flare hot spots are generated by lightpassing through a first reticle, and wherein the substantially uniformdose is provided by light passing through a second reticle.
 7. Themethod of claim 1 wherein the flare hot spots are generated by lightpassing through a first reticle, and wherein the substantially uniformdose is also provided by light passing through the first reticle.
 8. Themethod of claim 1 wherein at least some of the flare hot spots have anexpected intensity, and wherein the intensity of the substantiallyuniform dose is about the same as said expected intensity.
 9. A methodof forming a pattern of light intensity across an expanse ofphoto-imageable material, comprising: providing a reticle configured togenerate a primary pattern of different intensities from light passingtherethrough; stepping the reticle to different locations over thephoto-imageable material and providing light through the reticle at thedifferent locations to form a series of the primary patterns across thephoto-imageable material, the light also forming flare regions of lightintensity in locations of the photo-imageable material during theformation of the primary patterns; the locations in the photo-imageablematerial of the flare regions being defined as flare locations, and theremainder of the photo-imageable material being defined as a non-flarelocation; the flare locations having areas of maximum flare intensity;and providing a substantially uniform dose of light intensity to atleast the majority of the non-flare location and not to the areas ofmaximum flare intensity of the flare locations.
 10. The method of claim9 wherein the intensity of the substantially uniform dose is about thesame as the intensity at the areas of maximum flare intensity of theflare locations.
 11. The method of claim 9 wherein the substantiallyuniform dose is provided to a substantial entirety of the non-flarelocation.
 12. The method of claim 9 wherein the substantially uniformdose is not provided to any portion of any flare location.
 13. Themethod of claim 9 wherein the substantially uniform dose is providedprior to formation of the series of the primary patterns.
 14. The methodof claim 9 wherein the substantially uniform dose is provided afterformation of the series of the primary patterns.
 15. The method of claim9 wherein at least some of the substantially uniform dose is providedduring formation of the series of the primary patterns.
 16. The methodof claim 9 wherein the reticle is a first reticle, and wherein thesubstantially uniform dose is provided by light passing through a secondreticle.
 17. A method of utilizing a reticle to pattern an expanse ofphoto-imageable material, comprising: providing a reticle; the reticlebeing configured to be stepped across the expanse of photo-imageablematerial to provide a series of repeating patterns of light intensityonto the photo-imageable material; the reticle being divided into amain-field region and a compensating region; the main-field region beingconfigured to generate a primary pattern of different intensities fromlight passing therethrough, and having a first total area; thecompensating region having a second total area which is at least about25% of the first total area; the compensating region being configured toprovide a substantially uniform intensity across the entirety of thesecond total area from the light passing therethrough; and passing lightthrough the reticle and then onto the photo-imageable material; thelight passing through the main-field region forming the primary patternon the photo-imageable material, and forming one or more flare regionson the photo-imageable material outside of the primary pattern; thelight passing through the compensating region forming said uniformintensity across a segment of the photo-imageable material extendingsubstantially entirely from the primary pattern to at least one of theflare regions; said substantially uniform intensity being substantiallyequal to an intensity of the at least one of the flare regions.
 18. Themethod of claim 17 wherein the substantially uniform intensity issubstantially equal to a maximum intensity of the at least one of theflare regions.
 19. The method of claim 17 comprising stepping thereticle across the expanse of photo-imageable material; wherein thelight passing through the main-field region forms a plurality ofrepeating flare regions as the reticle is stepped across thephoto-imageable material; wherein the compensating region provides thesubstantially uniform intensity to some, but not all, of thephoto-imageable material outside of the plurality of flare regions;wherein the photo-imageable material outside of the plurality of flareregions receiving the substantially uniform intensity from thecompensating region is defined as treated photo-imageable material, andthe photo-imageable material outside of the plurality of flare regionsnot receiving the substantially uniform intensity from the compensatingregion is defined as non-treated photo-imageable material; wherein thereticle is a first reticle and the uniform intensity from thecompensating region is first uniform intensity; and further comprising:providing a second reticle; passing light through the second reticle togenerate second uniform intensity; the second uniform intensity beingsubstantially equal to the first uniform intensity; and impacting atleast some of the non-treated photo-imageable material with the seconduniform intensity and not impacting the treated photo-imageable materialwith the second uniform intensity.
 20. The method of claim 19 whereinsubstantially all of the non-treated photo-imageable material isimpacted with the second uniform intensity.
 21. The method of claim 17wherein the main-field region has a periphery comprising a totaldistance, and wherein the compensating region extends along at leastabout 50% of said total distance.
 22. The method of claim 17 wherein themain-field region has a periphery comprising a plurality of primarysides, and wherein the compensating region extends along all of saidprimary sides.
 23. The method of claim 17 wherein the main-field regionhas a periphery comprising four primary sides, and wherein thecompensating region extends along at least two of said four primarysides.
 24. The method of claim 17 wherein the reticle comprises asubstantially opaque material over a substantially transmissive base;and wherein the compensating region comprises a plurality ofclosely-spaced features formed within the substantially opaque material.25. The method of claim 17 wherein the closely-spaced features define agrating pattern.
 26. The method of claim 17 wherein the closely-spacedfeatures are substantially circular openings formed through thesubstantially opaque material.
 27. The method of claim 17 wherein: thereticle comprises a base having a base amount of transmission, a firstlayer over the base and having a first amount of transmission, and asecond layer over the first layer and having a second amount oftransmission; the base amount of transmission being greater than thefirst amount of transmission which in turn is greater than the secondamount of transmission; the main-field region has pattern featuresextending through both the first and second layers; and the compensatingregion has features extending through the second layer to the firstlayer, but does not have features extending entirely through the firstlayer.
 28. The method of claim 27 wherein the base consists essentiallyof quartz, the first layer consists essentially of molybdenum silicide;and the second layer comprises chromium.
 29. A reticle configured to bestepped across an expanse of photo-imageable material to provide aseries of repeating light-intensity patterns onto the photo-imageablematerial, the reticle comprising: a reticle substrate having amain-field region and a compensating region proximate the main-fieldregion; the main-field being configured to generate a primary pattern ofdifferent intensities from light passing therethrough; the main-fieldregion generating flare proximate the primary pattern when generatingthe primary pattern; the main-field region having a first total area;and the compensating region having a second total area which is at leastabout 25% of the first total area; the compensating region beingconfigured to generate substantially uniform intensity across theentirety of the second total area from light passing therethrough; saidsubstantially uniform intensity being about the same as an intensity ofthe flare.
 30. The reticle of claim 29 wherein the substantially uniformintensity is substantially equal to a maximum intensity of the flare.31. The reticle of claim 29 wherein the main-field region has aperiphery comprising a total distance, and wherein the compensatingregion extends along at least about 50% of said total distance.
 32. Thereticle of claim 29 wherein the main-field region has a peripherycomprising a plurality of primary sides, and wherein the compensatingregion extends along at least half of said primary sides.
 33. Thereticle of claim 29 wherein the reticle substrate comprises asubstantially opaque material over a substantially transmissive base;and wherein the compensating region comprises a plurality ofclosely-spaced features formed within the substantially opaque material.34. The reticle of claim 29 wherein the closely-spaced features define agrating pattern.
 35. The reticle of claim 29 wherein the closely-spacedfeatures are substantially circular openings formed through thesubstantially opaque material.
 36. The reticle of claim 29 wherein: thereticle substrate comprises a base having a base amount of transmission,a first layer over the base and having a first amount of transmission,and a second layer over the first layer and having a second amount oftransmission; the base amount of transmission being greater than thefirst amount of transmission which in turn is greater than the secondamount of transmission; the main-field region has pattern featuresextending through both the first and second layers; and the compensatingregion has features extending through the second layer to the firstlayer, but does not have features extending entirely through the firstlayer.
 37. The reticle of claim 36 wherein the base consists essentiallyof quartz, the first layer consists essentially of molybdenum silicide;and the second layer comprises chromium.